Search results for "Illite"
showing 10 items of 74 documents
Particle surface area dependence of mineral dust in immersion freezing mode: investigations with freely suspended drops in an acoustic levitator and …
2014
Abstract. The heterogeneous freezing temperatures of supercooled drops were measured using an acoustic levitator. This technique allows one to freely suspend single drops in the air without any wall contact. Heterogeneous nucleation by two types of illite (illite IMt1 and illite NX) and a montmorillonite sample was investigated in the immersion mode. Drops of 1 mm in radius were monitored by a video camera while cooled down to −28 °C to simulate freezing within the tropospheric temperature range. The surface temperature of the drops was contact-free, determined with an infrared thermometer; the onset of freezing was indicated by a sudden increase of the drop surface temperature. For compari…
Ice nucleation properties of the most abundant mineral dust phases
2008
[1] The ice nucleation properties of the nine most abundant minerals occurring in desert aerosols (quartz, albite, microcline, kaolinite, montmorillonite, illite, calcite, gypsum, and hematite) were investigated by environmental scanning electron microscopy (ESEM). In this instrument, the pure minerals are exposed to water vapor at variable pressures and temperatures. The crystallization of ice on the mineral particles is observed by secondary electron imaging, and the supersaturation for an activated particle fraction of 1–3% is determined as function of temperature. In all experiments, condensation of water prior to ice formation was not observed within detectable limits, even at water su…
Acid-Base Properties of 2:1 Clays. I. Modeling the Role of Electrostatics
2010
We present a theoretical investigation of the titratable charge of clays with various structural charge (sigma(b)): pyrophyllite (sigma(b) = 0 e x nm(-2)), montmorillonite (sigma(b) = -0.7 e x nm(-2)) and illite (sigma(b) = -1.2 e x nm(-2)). The calculations were carried out using a Monte Carlo method in the Grand Canonical ensemble and in the framework of the primitive model. The clay particle was modeled as a perfect hexagonal platelet, with an "ideal" crystal structure. The only fitting parameters used are the intrinsic equilibrium constants (pK(0)) for the protonation/deprotonation reactions of the broken-bond sites on the lateral faces of the clay particles, silanol, =SiO(-) + H(+) --=…
Bulk composition of northern African dust and its source sediments — A compilation
2013
Abstract This paper presents a review of bulk compositional data of northern African dust and its potential source sediments and includes elemental, isotope and mineralogical data. Northern African dust represents about one half of the total global atmospheric mineral dust burden, and its uplift, transport and deposition have strong impacts on climate and various terrestrial and marine ecosystems. The chemical data set shows, that an ‘average northern African dust’ exhibits comparable Si, Fe and Mn contents with respect to the average composition of the upper continental crust, is slightly depleted in the alkali metals K and Na, and enriched in Ti and P. However, the complete data set yield…
Paleoenvironmental evolution of the Pliocene Villarroya Lake, northern Spain. A multidisciplinary approach
2002
The Pliocene Villarroya basin fill consists of lacustrine and alluvial deposits over 100 m thick. The lacustrine deposits, up to 30 m thick, comprise three sequences. The two lower sequences consist of profundal, laminated deposits formed by mostly terrigenous facies that are overlain by charophytic carbonates and varves. The uppermost, third sequence made up of massive bioturbated mudstones corresponds to a very shallow lacustrine-palustrine environment. Bulk mineralogy comprises carbonates, clay minerals, quartz and feldspars. The carbonates are: exogenic, biogenic calcite and biogenic aragonite. Biogenic calcite constitutes ostracod shells and charophyte stem encrustations, whereas arago…
Suitability of Illite Based Clays of Latvia for Chemical and Thermal Activation
2014
Materials has been synthesized in the temperature range from 600-800 0C from illite based clays of Latvia under activation of KOH and NaOH solutions (4-6 M). Compressive strength and apparent porosity were measured. The effect of the concentration of KOH and NaOH solutions on the material mechanical properties was investigated by means of infrared spectroscopy (IR). Compressive strength data of the materials showed that via such activation building materials with good quality can be obtained.
Déclaration et vérification des créances. Faillite internationale d'un établissement bancaire, Créanciers étrangers, Eléments de preuve de l'existenc…
1996
International audience; (Com. 14 mai 1996, Wight ès qual. et autres c/ Mme Carrasset-Marillier, ès qual. et autres ; Com. 14 mai 1996, Société BCCI Luxembourg et autres c/ Mme Carrasset-Marillier, ès qual. et autres ; Com. 14 mai 1996, Société Holdings BCCI Luxembourg et autres c/ Mme Carrasset-Marillier, ès qual. et autres ; Com. 14 mai 1996, Société Crédit and Financial Corporation LTD et autres c/ Mme Carrasset-Marillier, ès qual. et autres ; Com. 14 mai 1996, Société International Credit Investment Compagny Limited et autres c/ Mme Carrasset-Marillier, ès qual. et autres ; Com. 14 mai 1996, Société Banco de Financiamento International c/ Mme Carrasset-Marillier, ès qual. et autres)
Two stories, one fate: age-heaping and literacy in Spain, 1877-1930
2021
This study looks at human capital in Spain during the early stages of modern economic growth. In order to do so, we have assembled a new dataset on ageheaping and literacy in Spain for both men and women between 1877 and 1930 based on six population censuses with information for 49 provinces. Our results show that age-heaping was less prevalent during the second half of the 19th century than previously thought and did not decrease until the early twentieth century. By contrast, literacy increased throughout the whole period. Interestingly, age-heaping and illiteracy rates depict similar spatial patterns which confirm the stark differences in human capital within Spain. Lastly, we raise crit…
Literacy in the cooperative sector evaluated through the reserve for cooperative education and training
2018
This study aims to evaluate the degree of legal-accounting literacy in cooperatives, having as an indicator the reserve for cooperative education and training, since this reserve is exclusive to the legal regime of cooperatives and which, due to its very specific purposes, presented itself as a mechanism that seeks to prevent or eliminate possible phenomena of illiteracy. This reserve ? which implements the cooperative principle of education, training and information ? addresses members, leaders and workers and aims to contribute to the development of the cooperative, by allowing the education of cooperators, an active membership, the professionalization of the employees and members of the …
Mass education or a minority well educated elite in the process of growth: The case of India
2013
Abstract This paper analyzes whether mass education is more growth enhancing in developing countries than having a minority well educated elite. Using Indian Census data as a benchmark and enrollment rates at different levels of education, we compute annual attainment levels for a panel of 16 Indian states from 1961 to 2001. Results indicate that if the reduction in illiteracy stops at the primary level of education, it is not worthwhile for growth. Instead, the findings reveal a strong and significant effect on growth of a greater share of population completing tertiary education. The economic impact is also found to be large: a one percent change in tertiary education has the same effect …